Crittall Steel Window Meets Tough Specification

07 March 2018

Latest advancements in high performance Crittall steel window design have been successfully combined with traditional aesthetics to meet the exacting standards demanded by one of the United States’ major Ivy League universities.

Both client and architect called for neo-Gothic style fenestration to blend with the design of classrooms, student accommodation, offices, libraries and dining halls for the new college buildings.

A variety of bespoke window shapes was required, some with curved tops, others with Gothic-style heads and trefoils, but all had to satisfy tough thermal and acoustic requirements.

Crittall turned to its Berkeley range which was modified with the addition of triple glazing comprising an exterior true leaded glass panel separated via a vented cavity to an interior insulating glass unit.

An exterior putty-effect sloping glazing detail was used to replicate old putty-glazed windows, but using an interior glazing bead for ease of servicing. The slim sightlines that are a hallmark of Crittall steel windows perfectly matched the characteristic appearance of traditional, single pane, putty glazed fenestration.

Traditional welded steel bullet style hinges, hardware patterns and back plates were incorporated but offering modern functionality and safety.

The bespoke Berkeley windows were hot dipped galvanized and polyester powder coated so as to achieve durability combined with low maintenance. The system also had a matching-profile variance offering a 45-minute UL fully-accredited and tested fire rating for particular parts of the building.

This specially designed windows contributed to the building meeting the Gold certification standard of the Leadership in Energy and Environmental Design (LEED) rating system devised by the United States Green Building Council. This was also achieved thanks to the combination of strong, slim steel profiles and the advanced glazing specification that combined to afford high solar gains.

Other features specific to the technically challenging contract included the client’s requirement that the system could be “bench-glazed” off-site and brought to the building ready for fast-track installation. Window clips were pre-installed in the window perimeters to make this possible.

The Berkeley windows also needed to provide specific perimeter detailing to ensure correct watertightness marrying together the custom window profile with period stone exterior facade detailing and the demands of new-build insulation. This new detailing was designed specifically for the job and tested in a mock-up exterior wall on-site prior to the installation proper.

Says Crittall Managing Director Stuart Judge, “We were given the competitive challenge to develop a new product, designed in collaboration with the architects and contractors – to meet stringent performance and technical criteria, coupled with aesthetic stipulations and engineered to ensure fast track installation on these significant builds. This has been achieved.”